The Miracle Fat for Eczema--GLA
May 28, 2003
It is thought that essential fatty acids (EFAs) play a role in the development of atopic disease. Linoleic acid (LA), part of the n-6 EFA series, is derived from food and subsequently converted into gamma-linolenic acid (GLA) and longer-chain polyenes (LCPs) such as dihomo-gamma-linolenic acid (DGLA) and arachidonic acid (AA). Although LCPs of the n-3 EFA series can be derived from alpha-linolenic acid (ALA), the major source of n-3 LCPs is food.
Studies have found higher concentrations of LA and lower concentrations of LCPs in the blood of patients with atopic dermatitis (eczema). Additionally, newborns with a family history of atopic disease have been found to have lower concentrations of n-6 LCP in umbilical cord blood prior to developing atopic disease (AD).
Researchers suggest that this may be due to a reduced conversion of LA into GLA and subsequent LCPs, possibly as a result of impaired activity of the enzyme linoleoyl-CoA desaturase (delta6-desaturase).
Further, other studies showed that breast milk from mothers whose infants subsequently developed AD contained less n-6 LCP than milk from mothers of unaffected infants. Recently, some brands of infant formula are being enriched with LCPs, such as GLA. Prior to this, infant formulas, unlike breast milk, contained only LA and ALA as EFAs.
Several studies have looked at whether GLA supplementation in patients with AD could reduce the severity of existing eczema, however results have been inconsistent.
An additional study has found a possible role of GLA in the prevention of atopy in early life. Researchers based their suggestion on several observations: mothers of atopic infants have lower concentrations of n-6 LCP in their breast milk than mothers of non-atopic infants; the amount of EFAs in newborns is dependent on their supply while in utero and later on diet of either breast milk or infant formula; and infants who have atopic symptoms at 1 year of age have significantly lower mean concentrations of n-6 LCPs in umbilical cord blood and in serum at 1 months and 3 months of age than infants with no atopic symptoms.
Moreover, prostaglandins derived from n-6 LCPs are thought to play a role in the maturation of the immune system.
Since the conversion of LA to GLA is thought to affect the rate of the total chain of conversions, supplementation with GLA in infancy might compensate for the lower n-6 LCP concentrations and therefore prevent atopy or decrease its severity in infants, especially if the mother is predisposed to AD.
Among four trials, which investigated whether GLA supplementation protects against the development of atopy in formula-fed infants with atopic mothers, one showed that GLA supplementation reduced the severity of eczema compared with a placebo.
According to researchers, the results show an effect of GLA on the severity of AD, which indicates that GLA supplementation has a beneficial effect on the inflammatory component of AD.
American Journal of Clinical Nutrition April, 2003;77(4):943-51 (Free Full Text Article)